Method and apparatus for making elastic coil cables with longitudinal ends



@ch 26 1948. R. D. COLLINS METHOD AND APPARATUS FOR MAKING ELASTIC COIL CABLES WITH A LONGITUDINAL END Filed April 12, 1945 Patented Oct. 26, 1948 METHOD AND APPARATUS FGR MAKENG ELASTIC COIL CABLES i /1TH LQNG-ITLTU- DINAL ENDS Ral h 1). Collins. Beverly Hills, Califi, assignmof one-half to Kellogg Switchboard and un Company, a corporation oi Illinois Application April 12, 1945, Serial No. 53$,fi-i3 2 Claims. 1

This inven ion relates to elastic coil structures with longitudinal ends.

It is now well known that retractile extensible extension cords or cables, for various purposes, principally electrical, may be satisfactorily constructed by providing a conductor or a plurality of conductors with a covering or sheath of incompletely vulcanized rubber or the like, then closely coiling it into the form of a hair, and then vulcanizing it, after which the cable will be readily extensible, as. for example, for extension cord purposes, without damage thereto while being automatically retracted by its own resilience to closely coiled helical forma tion when released, and that the resilience of the cable may be enhanced by reversing the direction of the coils as broadly disclosed and claimed in the Campbell Patent No. 2,173,096.

The present invention aims to provide an improved method and means for making cables of this class, economically and expeditiously in quantity production, with longitudinal ends to provide say connecting tails therefor.

The invention will be readily understood by reference to the following description, taken to gether with the accompanying drawings, show ing an illustrative embodiment of the invention, and in which drawings- Figure 1 is a view of one means employed in accordance with the present disclosure;

Figure 2 is a section taken on the line 22 of Figure 1;

Figure 3 is another section taken on the line 3-3 of Figure l and looking in the opposite direction as indicated by the arrows;

Figure 4 is a View, somewhat reduced, of a cable formed in accordance with the present disclosure after reversal of the direction of the coils; and

Figure 5 is a View of another means employed in accordance with the present disclosure.

Referring in general to the drawings, it will be understood that the cable includes a coiled portion and an uncoiled portion which is adapted to serve as a connecting tail for the cable.

In accordance with the present invention and turning first to Figure 1, a coiled cable portion is here given the numeral ii and an uric-oiled portion the numeral l2. The mandrel I3 is provided upon which is wound, before vulcanizing, the coiled portion H of the cable iii, which as best seen in Figure 2 may comprise one or more conductors M which may be twisted together and encased in a covering sheath iii of vulcanizable material such as rubber or a rubber sub stitute of which there are many now on the market among the synthetic elastomers, the product known as Buna S having been used found to be su table.

One end of the coiled cable portion ll may be e1 83 from uncoiling as by a clip portion is then wound to the ..:rel to such an extent as may d, whereupon the cable may be itself as by the uncoiled portion of the cable occurring between the Jed portion where the cable is c th s instance, the uncoiled portion it of the cable is he d parallel with the man-- drel it and extends longitudinally of the coiled por ion ii and lapping the latter but spaced h refrom by holdlg means represented in this nee by a metal semi-cylindrical or trough-- like ce iii in which the cable portion l2 lies and which spaces the uncoiled portion $2 from mandrel end from the coiled cable portion l l as next described.

At one end, hat is adjacent the bight ll of the cable, the trough piece ill is arcuately bent as at ill to extend away from the mandrel and the extreme end or the arcuately bent part i!) is curvedly notched at to receive the mandrel therein and the trough piece is thus held to the mandrel at this end by the cable itself which ex ends thereover. At the place where the cable enters the trough piece, for example as at El the trough piece is curvilinear, which is to say that it is cut away on rounded lines, avoiding sharp edges or corners which might mark the initially soft flexible material of the cable cover ing sheath l5.

At its other end, the trough piece it is spaced from he mandrel and the coiled. portion of the cable, and, at the same time, both the trough piece and the uncoiled cable portion l2 may be held in the position shown by expedients such as the clip which two spring jaw portions, a pair at each end. One of these pairs of jaws is represented by the numeral 23 and comprising a pair of spring jaws which are adapted to slip onto the mandrel against their own resilience and yieldingly grip the mandrel, the latter being cut away as desired as at 24 to provide flat sur faces which the spring jaws 2-3 may grip and prevent rotation of the clip 22 on the mandrel. At its other or outer end, the spring clip 22 may comprise another spring jaw portion 25 in which the trough piece ES with the uncoiled portion 52 of the cable may be received, the jaws being of sinuous formation to permit entry into or removal therefrom of the trough piece and cable while gripping the latter parts when therein. The two similar parts of the clip which provide the pairs of jaws may be riveted together as at 26.

The structure shown in Figure 1, including the mandrel l3andthe cabl'e.-.l0 thereon aashown, is subjected to'a vulcanizing treatment, of any suitable character, to cure and set the rubber-like material of the cable, and, when this has been: done, the cable I 0 is then removedfromithemanrdrel. Thereupon the coils of 'theicablearerdeslrably reversed in direction of pitch, so that the coil turns form a right-hand screw-thread, so to speak, instead of a left-hand screw-thread asiin Figure 1. This reversal of the coil, as shown; in Figure 4, will advantageously cause the longitudinally extending or uncoiled: portion of the cable such as l2 to extend in the opposite axial direction from that which it extends in Figure 1, and namely, away from the coiled portion and not'tlapping it as in Figure 1". Thusin the corn-- plet'ed' a'ble or extension cord of Figure 4, the:

cable part I'Zprovides a suitable connectingtail for the cable, the wires l4. of'this'connecting tail beingsuitably bare'd and soldered as may be desired.

In the modification shown in Figure 5, the. cable 21 has'the'coil'ed portion 29- and uncoiled or longitudinally extending portion 29. In this instance, the mandrel 30 is hollow and after the g;

coiled'portion 28 ofthe cable 2'! has been wound upon the mandrel as shownin Figure 5, the uncoiled portion 29-. is' inserted or tucked into the interiorbore of the mandrel, and thus extending not only longitudinally of and lapping the coiled portion 28- of the cable but also within the coiled portion.

Here again, where the uncoiled. portion 29 of the cable 27' enters the mandrel and in the vicinityof-the bight' 38 of the cable between the co led and'uncoiled-portions, the mandrel is desirably slotted as at 32, the edges of the slot being arcuate as at 33 and thus-providing a curvilinear formation which avoids sharp edges' or. corners which'might'mark thesoftmaterial of the'cable L Thesame-thing: may occur 'at the other or'lefthand end (not shown) of the structure shown in Figure 5.

Thereupon, the. structure shown in. Figure 5 is vulcanized: as: already referred to with, reference to: Figure 1, and, after vulcanization, the. cableof Figure 5 is removedfrom the mandrel and: may have'itscoilsreversed as'shown in Fig"- ure; 4;.whereuponthe uncoiled or; longitudinally extending portion 29 of the cable 2! will extend outwardly awayfrom the coiled portion to. form a; connecting tall as. does theportion 12 of the.

cablez I 0 seen in, Figure 4.

A function accomplished bythe structure and method of Figure 5, beyond that already described, is that the connecting tail :29 of the cable: 2.7 may be-produced'with a. less degree of vulcanizationcrcurethan that of the coiled portion 28; .sinceithe portion 29- is-protected by the man-- drel. 30 from themaximum heat of the furnaceor the like in. which the-cable isvulcanized; and.

consequently the rubber-like sheath. l5. of the cable connecting tail 29 is kept relatively softer than that of the coiled portion 28. When the connecting tail 29 is soldered to an electrical device, the material 15 thereof may be somewhat molded to and further vulcanized with a similar rubber likecovering which may be on such electrical device;

The invention is not limited to details of construction or operation here shown for purposes of. exemplification andsuch changes may be made asafa-ll within the scope of the appended claims without: departing therefrom.

The invention having been described, what is here claimed is:

1*. The method of making elastic coil cables with uncoiled ends, embodying a vulcanizable material, which: is characterized by the steps of forming a portion of the cable into a coil, providing another integral materially extending portion of the cable uncoiled, bending the uncoiled portion at its juncture with the coiled portion,

holding said uncoiled portion spaced from thecoiled portion and extending in a direction lappingly of' the coiled portion, supporting the uncoiled portion at a place therealong spaced from,

the place where the uncoiled portion is bent, vulcanizing the material while maintaining said" mandrelfor supporting an uncoiled portion of the cable spaced from and in a direction lappingly' of the coiled portion, said means preventing the uncoiling of' said coiled portion and the coiling ofsaid uncoiled portion during subsequent vulcanization of the material on the mandrel,

whereby to form a coiled structure having an uncoiled end of predetermined formation, wherein the last mentioned means includes a curvilinear'guide formation accommodating the bight of the cablebetween the coiled' and uncoiled portions'to avoid marking the cable at said bight.

RALPH D. COLLINS.

REFERENCES CITED The. following references. are of record in the file of this patent:

UNITED STATES PATENTS 

